Technical Field
Embodiments of the subject matter disclosed herein relate to engines, engine systems, and methods for operating engine systems, for example.
Discussion of Art
Exhaust gas recirculation (EGR) lowers peak combustion temperatures and hence lowers NOx production, and thus engine systems may be configured to tightly control EGR in order to maintain emissions under designated limits. One or more exhaust gas flow control valves in the exhaust of an engine system may be adjusted in order to control the amount of EGR directed to the engine and/or control the amount of boost pressure. Accurate control of the amount of EGR supplied to the engine relies on accurate knowledge of each exhaust valve position as well as accurate knowledge of the amount of driving current required to reach a desired exhaust valve position. However, valve-to-valve variability and day-to-day wear may introduce inaccuracies into the exhaust valve position control.